Commit 6d0ce46a authored by Eric Dumazet's avatar Eric Dumazet Committed by Jakub Kicinski
Browse files

vrf: use RCU protection in l3mdev_l3_out() 



l3mdev_l3_out() can be called without RCU being held:

raw_sendmsg()
 ip_push_pending_frames()
  ip_send_skb()
   ip_local_out()
    __ip_local_out()
     l3mdev_ip_out()

Add rcu_read_lock() / rcu_read_unlock() pair to avoid
a potential UAF.

Fixes: a8e3e1a9 ("net: l3mdev: Add hook to output path")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Reviewed-by: default avatarDavid Ahern <dsahern@kernel.org>
Reviewed-by: default avatarKuniyuki Iwashima <kuniyu@amazon.com>
Link: https://patch.msgid.link/20250207135841.1948589-7-edumazet@google.com


Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 90b2f49a

include/net/l3mdev.h

+2 −0
Original line number Diff line number Diff line
@@ -198,10 +198,12 @@ struct sk_buff *l3mdev_l3_out(struct sock *sk, struct sk_buff *skb, u16 proto) 
	if (netif_is_l3_slave(dev)) {

		struct net_device *master;



		rcu_read_lock();

		master = netdev_master_upper_dev_get_rcu(dev);

		if (master && master->l3mdev_ops->l3mdev_l3_out)

			skb = master->l3mdev_ops->l3mdev_l3_out(master, sk,

								skb, proto);

		rcu_read_unlock();

	}



	return skb;